What is Psoriatic Arthritis?

Psoriatic arthritis is a form of arthritis that exclusively affects people with the skin condition psoriasis. Psoriasis is a common, chronic (long-term), inflammatory disease caused by the overproduction of new skin cells, which causes a rash that is pink/red with silver on white skin or purple/pink with silver on black skin. Following the diagnosis of psoriasis, approximately 30% of patients will develop psoriatic arthritis.¹

For most patients diagnosed with psoriasis, psoriatic arthritis develops approximately 10 years after the diagnosis. However, some people may experience joint symptoms prior to, or at the same time as the onset of visible skin symptoms. Common joint problems include pain, swelling, and stiffness. This long term condition currently has no definitive cure, however, some treatments are still available that reduce the inflammation and swelling associated with thiscondition. Early diagnosis and treatment reduce the likelihood of long-term joint damage caused by the disease.

Overview

Psoriatic arthritis is a form of inflammatory arthritis that only affects people with psoriasis. A diagnosis of this disease can  have far-reaching consequences , however, I hope this page can provide you with the information needed to manage your disease successfully. This page will discuss the causes of psoriatic arthritis, its signs and symptoms, and the currently available treatment options.

Causes of psoriatic arthritis

The exact causes of psoriatic arthritis are not fully known, however, studies have shown that psoriatic arthritis is its own independent inflammatory arthritis as opposed to a coincidental occurrence of rheumatoid arthritis and psoriasis. Studies have indicated that the primary cause of this disease is genetic, therefore, it is more likely to affect those with a family history of psoriasis or psoriatic arthritis. If someone has a genetic predisposition to psoriatic arthritis then environmental trauma may trigger the disease onset later in life.² Environmental trauma associated with the development of psoriatic arthritis includes infections (viral and bacterial), physical injury, obesity, and lifting heavy weights.

These genetic factors associated with the development of psoriatic arthritis cause an overactive immune system, which leads the body’s immune system to attack healthy cells. This overactivity results in chronic inflammation, which is long-term and recurrent. In the case of psoriatic arthritis, the immune system mistakenly attacks and destructs the healthy joint tissues. 

Currently, some genetic markers are being investigated that correlate with the development of psoriatic arthritis which are not present in individuals only affected by the skin manifestation of psoriasis. However, this does not clearly explain why some people with psoriasis develop psoriatic arthritis, whilst others do not.³

Signs and symptoms of psoriatic arthritis

The development of the signs and symptoms varies between individuals. Some people may develop only mild symptoms, while others may experience a faster escalation of the disease with more severe symptoms, and another group of people may develop localised psoriatic arthritis in a joint following injury. Psoriatic arthritis can develop at any age, including childhood. 

Common symptoms include:

• Pain, tenderness, stiffness, and swelling in any joint, tendon, or ligament in the body (commonly affecting hands, feet, knees, and ankles, but can include the fingertips and spine)
• Fatigue
• Reduced range of motion
• Swelling of the fingers and toes
• Silent or without any symptoms
• Nail changes (small dents, or separation from the nail beds)

It should be noted that the severity of psoriasis symptoms is not indicative of psoriatic arthritis disease severity. ^{4, 5}

Management and treatment for psoriatic arthritis

There is no definitive cure for psoriatic arthritis. Current management and treatment options aim to control the inflammation in the affected joints to alleviate joint pain and disability, slowing the progression of the disease and improving the quality of life whilst controlling symptoms of the skin condition. 

Your healthcare provider will help you find the correct treatment plan depending on the severity of your disease and the affected joints. Finding the appropriate treatment plan for you can take time as it usually requires multiple drug trials. Psoriatic arthritis is treated with the same standard therapies as poriasis, spondylitis. and peripheral arthritis. It should be known that antimalarial drugs should be avoided as they can aggravate the skin symptoms of psoriasis.^{2, 5}

Medicines used in the treatment of psoriatic arthritis can include:

Disease-modifying anti-rheumatic drugs (DMARDs)

DMARDs aim to control the persistent inflammation in the joints. The use of these drugs early following this disease diagnosis can greatly reduce the risk of permanent joint damage. The most commonly used drug to treat psoriatic arthritis is methotrexate, amongst others. Side effects of DMARDs can include lung inflammation, scarring (fibrosis), bone marrow suppression, upset stomach, loss of appetite, fatigue, and liver damage. If conventional DMARDs have been unsuccessful, targeted synthetic DMARDs may be used. Side effects of these drugs may be much more severe and can include cancer, heart-related issues, and a risk of blood clots in the lungs.There is also a subset of DMARDs more commonly referred to as biological agents. These biological treatments target various immune pathways. A side effect of these drugs is an increased risk of infection.⁴

Non-steroidal anti-inflammatory drugs (NSAIDs)

Mild cases of psoriatic arthritis may be treated with NSAIDs, these drugs can also be used in conjunction with other treatment options for moderate and severe cases of psoriatic arthritis. One example available with no prescription required is Ibuprofen. If stronger NSAIDs are needed, these are available on prescription only. Side effects of these types of drugs can include heart problems, stomach irritation, and damage to the kidney and liver.⁴

Newer oral medication

For those who cannot or do not wish to be treated with DMARDs, there is a new drug known as Apremilast now available. It works by controlling inflammation within cells. This drug is intended for those with mild or moderate psoriatic arthritis, its side effects can include headaches, diarrhoea and nausea.⁵

Complementary therapies

Currently there is little evidence to suggest complementary therapies used to treat psoriatic arthritis work. However, there is often a keen interest to explore non-medical potential therapies. In this case, it is best to speak to your healthcare provider to see if any complementary therapies are appropriate to you and whether they can be integrated into your treatment plan. Lifestyle changes are known to reduce symptoms of psoriatic arthritis. These lifestyle changes include:⁵

• Maintaining a healthy weight - This helps avoid unnecessary strain on the joints, and as a result, reduces pain and enables the medication to work more efficiently
• Reducing alcohol consumption - Alcohol can interact with your medication, increasing the side effects whilst decreasing its efficiency
• Stopping smoking - This reduces your risk of developing psoriasis, or worsening your current Psoriatic symptoms
• Protecting joints - Altering how you conduct everyday tasks to minimise the impact on your joints andreduce pain
• Regular exercise - Doing regular exercise that is gentle on the joints helps maintain their mobility

FAQs

How is psoriatic arthritis diagnosed

Contact your GP if you are experiencing any of the aforementioned symptoms. If your GP thinks you might have psoriatic arthritis they will refer you to a joint condition specialist (known as a rheumatologist). Your rheumatologist will then be able to diagnose you with psoriatic arthritis based on your medical history, present symptoms, x-rays, and blood tests. These blood tests will also  rule out other types of arthritis including osteoarthritis, spondylitis, and rheumatoid arthritis. 

How can I prevent psoriatic arthritis

As psoriatic arthritis arises as a result of multiple genetic and environmental factors, some of which are still unclear,  there is no current way to prevent an individual from developing this condition.^{6, 7}

Who is at risk of psoriatic arthritis

People who suffer from Psoriasis are at the greatest risk of psoriatic arthritis disease development. Of those diagnosed with psoriasis, 30% will go on to develop psoriatic arthritis. Psoriatic arthritis affects both who are assigned female at birth (AFAB) and assigned male at birth (AMAB) equally.¹ Individuals with a family history of either psoriasis or psoriatic arthritis are also at risk of developing this condition. Many people with the disease will also have a sibling or parent who also has it. Furthermore, although psoriatic arthritis can develop at any age, but the most common age for the disease onset is between 30 and 55 years of age.⁵

How common is psoriatic arthritis

Worldwide there are approximately 125 million people living with psoriasis, which is around 2-3% of our total population. According to the national psoriasis foundation, 3 in 10 people with psoriasis will develop psoriatic arthritis.

When should I see a doctor

You should seek doctor’s advice if you suffer from persistent stiffness, swelling, or pain in your joints. You should do this regardless of whether you have been diagnosed with psoriasis or not. Having a check-up at least once a year is recommended for those whohave been diagnosed with Psoriasis. This is to monitor your condition and assess the development of Psoriatic arthritis.

Summary

Psoriatic arthritis is an arthritic disease that people with psoriasis are susceptible to. The exact cause of psoriasis and psoriatic arthritis is still unclear as it is a multifaceted disease, however, several genes have been linked to the development of psoriasis. The onset of psoriatic arthritis, the signs and symptoms, and the prognosis can vary from patient to patient depending on the severity of the condition. If you are experiencing persistent pain, swelling, or tenderness in the joints seek medical advice even if you've been diagnosed with psoriasis before. Currently, there is no definitive cure for this condition, however, there are treatments that can help alleviate your symptoms, reduce the risk of permanent joint damage and therefore improve your quality of life. As with most health conditions, the sooner you begin treatment the better your prognosis will be.